A ghost playing video games in your room will have a side effect on your electric bill, as Juugo finds out the hard way. After turning down an allowance from his father, he visits a secret club dedicated to helping students find a little extra work on the side.

The self-proclaimed "master detective" Tensai Ikkyu and her maidservant, Daruku, enter the island school, hot on the trail of the treasure stolen at the end of episode one. They cross paths with Juugo Yama, their suspect, and the trio joins the school's Adventure Club, tasked with hunting down Nanana's lost cache.

Nanana Ryuugajou was a special girl - she and her friends together tracked down some of the world's most ludicrous treasures. However, one day, in her apartment, Nanana was killed. Ten years later, Juugo Yama moves to the man-made island Nanana called home and only has enough money to rent her former room...which she still haunts to this day.